Displacement ductility ratio-based flexural design approach of reinforced concrete slender shear walls

Abstract

This study established a new flexural design approach for reinforced concrete shear walls based on the displacement ductility ratio. The moment–curvature relationship of a shear wall section was generalised by interpolating the points of yielding, ultimate flexural capacity and 80% of ultimate flexural capacity after the peak point. To estimate the curvature of the shear walls at the post-peak branch, the concrete strain at the extreme fibre was calculated by considering the volumetric index of the lateral reinforcement and the concrete stress reduction factor derived from the stress–strain relationship of confined concrete. The calculated curvature points were converted to lateral displacements using the moment area method associated with the equivalent plastic hinge length. To simply evaluate the displacement ductility ratio of shear walls, an extensive parametric study was conducted in accordance with the above procedure. The proposed moment–curvature relationship and displacement ductility ratio equation for shear walls were verified through comparisons with experimental results compiled from the available literature. Ultimately, the proposed models were applied to the development of a flexural design of shear walls and a design diagram to determine the details of boundary element length for a targeted ductility ratio.